The effect of Moringa leaf supplementation on the reduction of copper toxicity in fish Cyprinus carpio. The gill tissue elicited the highest copper accumulation followed the liver in C. carpio. Copper accumulation was significantly (P<005) high in (MO) group and it gradually decreased with an increasing the levels in (M1 –M4) groups. The maximum reduction of copper accumulation in tissues occurred with the supplementation of 30% (M2) Moringa diet followed by 40% (M3) and, 50% (M4) and 20% M1) Moringa diet respectively in both size groups C. carpio. The elimination of accumulated copper through feces and water increased with increasing the dietary levels of Moringa diet in small and large size C. carpio.